Integrated fault diagnosis and prognosis for in-vehicle communications

ABSTRACT

A method of diagnosing a fault in an in-vehicle communication system. The in-vehicle communication system includes a transmitting node, at least one receiving node, and a network communication bus coupling the transmitting node to the at least one receiving node. A message is transmitted from the transmitting node to the at least one receiving node over the communication bus. A fault detection technique is applied within the transmitting node for detecting a fault within the transmitting node. A fault detection technique is applied to the at least one receiving node for detecting a fault within the at least one receiving node. A fault detection technique is applied within the network communication bus for detecting a fault within the communication bus. An analyzer collectively analyzes results from each respective detection technique for isolating a fault within the in-vehicle communication system.

BACKGROUND OF INVENTION

An embodiment relates generally to in-vehicle communication diagnostics.

A controller-area network (CAN) is a vehicle multiplex bus standardintended to allow electronic control units (ECUs) and other devices tocommunicate with one another without a central or host controller of thebus. Vehicle systems and subsystems have numerous ECUs that controlactuators or receive vehicle operation data from sensing devices.

CAN systems are asynchronous broadcast serial buses which communicatemessages serially. Only a single message is communicated on acommunication-bus at a time. When a message is ready to be transmittedonto the communication bus, the CAN-controller controls the messagetransfer on the bus. Since messages are transmitted serially, variousnodes on the communication bus await a time to transmit. When a messageis ready to be transmitted onto the communication bus, the buscontroller controls the message transfer on the bus. If more than onemessage transmission is initiated simultaneously by multipletransmitters, the more dominant message is transmitted. This is known asan arbitration process. A message with a highest priority will dominatethe arbitration and a message transmitting at the lower priority willsense this and wait. Therefore, it is pertinent to maintain a duty cyclefor transmitting messages so that a backlog does not occur.

An error in the in-vehicle communication system is detected by thereceiver based on a time-out occurring. That is, since messages aretransmitted based on a duty cycle (e.g., 10 msec), if a receiver doesnot receive a message at the allocated time, then an assumption may bemade that an error has occurred within the system. The error may occurat the transmitting node or in the communication bus; however, there isno effective method for identifying where the fault exactly occurred inthe conventional in-vehicle communication system utilizing the time-outtechnique.

SUMMARY OF INVENTION

An advantage of an embodiment is an identification of an isolated faultwithin an in-vehicle communication system utilizing node leveldiagnostics and network level diagnostics. The system individuallyanalyzes communication layers in each ECU of a CAN system. After eachcommunication layer is analyzed and potential faults are detected, eachof the diagnostic results for the communication layers of ECU arecollectively analyzed for further isolating the fault. In addition,fault detection is performed on a communication bus for identifying apotential fault within the communication bus. An integrated networklevel diagnostic analysis is performed on integrated diagnostic dataobtained at the ECU level node and the network level diagnostic data forcollectively isolating the fault within the in-vehicle communicationsystem.

An embodiment contemplates a method of diagnosing a fault in anin-vehicle communication system, the in-vehicle communication systemincluding a transmitting node, at least one receiving node, and anetwork communication bus coupling the transmitting node to the at leastone receiving node. Each of the transmitting node and the at least onereceiving node including a plurality of communication layers forservicing messages within each of the nodes within the in-vehiclecommunication system. The plurality of communication layers of each nodeincluding at least an application layer, an interaction layer, a datalink layer, and a physical layer. A message is transmitted from thetransmitting node to the at least one receiving node over thecommunication bus. A fault detection technique is applied within thetransmitting node for detecting a fault within the transmitting node. Afault detection technique is applied to the at least one receiving nodefor detecting a fault within the at least one receiving node. A faultdetection technique is applied within the network communication bus fordetecting a fault within the communication bus. An analyzer collectivelyanalyzes results from each respective detection technique for isolatinga fault within the in-vehicle communication system.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exemplary schematic of a block diagram of a controller areanetwork communication system.

FIG. 2 is a block diagram of the integrated fault analysis detectionsystem.

FIG. 3 is a flow diagram for performing integrated diagnostic andprognosis analysis for the in-vehicle communication system

DETAILED DESCRIPTION

There is shown in FIG. 1, a controller area network (CAN) system 10. TheCAN system 10 includes a plurality of electronic control units (ECUs)12-18 coupled to a communication bus 20 which allows the ECUs tocommunicate with one another. Each of the plurality of ECUs 12-18 arecoupled to one or more sensors, actuators, or control devices (e.g.,application components). The application components are not directlyconnected to the communication bus 20, but are coupled through therespective ECUs. The application components could also be softwarecomponents in ECUs. A single control feature may span across multipleapplication components and involve control messages from source to adestination ECU via one or more intermediate processing/control ECUsattached to the same communication bus. For the purposes of thisinvention, it is understood that CAN systems are known in the art andthat ECUs, application devices, CAN controllers, and transceivers arereferred to as nodes and the details of their composition will not bediscussed in detail herein.

In FIG. 1, messages are serially communicated over the communication bus20 to each ECU 12-18 as shown. That is, only a single message may betransmitted over the communication bus 20 at one instance of time. Forexample, in FIG. 1, node N1 transmits a message on the communication bus20 and is received by nodes N2, N3, and N4. Each of the nodes N2, N3,and N4 receives and processes the message transmitted by the node N1.Each message communicated serially over the communication bus istransmitted on a periodic basis (e.g. 10 msec). As a result, arespective node expects to receive a message substantially every 10msec.

Each of the electronic control units (ECUs) within each node includes aplurality of communication layers for servicing messages that arereceived from other nodes or are being prepared for transmission toother nodes. The plurality of communication layers for each ECU includesan application layer 22, an interaction layer 24, a data link layer 26,and a physical layer 28. Each of the plurality of layers provides afunction for servicing the message.

The application layer 22 interacts with a respective softwareapplication for implementing a communicating device. The applicationlayer 22 identifies a communication entity for determining its identity;for determining resource availability that includes determining whethera network for communication exists; and for synchronizing communicationsbetween the applications that require cooperative communications.

The interaction layer 24 attaches the signal from the application layerinto a frame that is passed on to the data link layer 26.

The data link layer 26 provides both functional and proceduralprocesses, protocols, and specifications to transfer data betweenrespective ECUs within the in-vehicle communication network.

The physical layer 28 sets forth the electrical and physical hardwareand specifications for the communicating devices. The physical layerdefines the mode of transmission (e.g., optic, copper), connector type,connector shape, electrical pin configuration, voltages, cablespecifications, network adapters, and bus adapters.

Each node N1, N2, N3, and N4 will include a set of communication layersfor servicing a message received by another node or a message fortransmission by the node itself.

Faults may occur at any point within the CAN system 10 including theECUs, connections, or the communication bus. Such faults may includehardware faults, including but not limited to, a controller, connector,transceiver, wires, and software. Therefore, fault diagnostic techniquesare executed at an ECU node level and at a network level.

FIG. 2 illustrates the fault detection analysis performed on both theECU node level and the network level. The first ECU 12 communicatesmessages with the second ECU 14 via the communication bus 20. The firstECU 12 is part of the transmitting node and the second ECU 14 is part ofthe receiving node.

For ECU node level diagnosis and prognosis, fault detection analysiswill be performed on each communication layer independently fordetecting a fault. For example, a first fault detection technique 30 isperformed on the application layer 22, a second diagnostic technique 32is performed on interaction layer 24, a third diagnostic technique 34 isperformed on the data link layer 26, and a fourth diagnostic technique36 is performed on the physical layer 28.

Diagnostic techniques that may be performed on the physical layer 28include, but are not limited to, time-domain reflectometry (TDR),frequency-domain reflectometry (FDR), spread-spectrum (TDR),noise-domain reflectometry (NDR), open/short circuit, fault location,and time of occurrence.

Diagnostic techniques that may be performed on the data link layer 26include, but are not limited to, cyclic redundancy checks (CDC),acknowledgement, bit-stuffing, faulty message ID, and time ofoccurrence.

Diagnostic techniques that may be performed on the interaction layer andapplication layer include, but are not limited to, time-out, sequencenumber, CRC, delay, out of order.

Each respective layer reports its detections to an ECU node leveldiagnostic module 38 for node level integrated diagnostics. ECU 12 andECU 14 each include an ECU node level diagnostic module 38 that collectsand manages the node level multi-layer diagnostic data. Each ECU nodelevel diagnostic module 38 performs diagnostics on the communicationlayer data and isolates any sender, receiver, or bus faults within theECU. For example, a time-out diagnostic technique is performed on theapplication layer which indicates that information has not been receivedin the allocated time frame. Typically, a length of time for a time-outincludes the expected duration of time between message transmissions.The diagnostic data from each of the communication layers are thenprovided to the ECU node level module 38 so that each of the diagnosticresults from the communication layers can be analyzed collectively.Performing analysis at an integrated node level assists in isolating thefault. That is, fault detection at the communication layer may identifythat a fault exists in the in-vehicle communication system, but does notnecessarily identify exactly where the fault exist. Performingintegrated analysis collectively on the diagnostic data of thecommunication layers within a respective ECU further assists inisolating the fault.

After each of the ECUs perform node level integrated diagnosticanalysis, the diagnostic analysis data from each of the ECUs istransmitted to a network level diagnostic analyzer 40 for integratednetwork analysis. The network level diagnostic analyzer 40 represents acentralized node for collecting all other diagnostic results of all theECUs within the in-vehicle communication system and performing thenetwork level integrated analysis. Alternatively, a distributedtechnique may be used where there is no centralized dedicated node forthe performing network level analysis. In the distributed technique, thenetwork level diagnostic analyzer includes a plurality of ECUs areinvolved in performing the network level integrated analysis throughback-and-forth communications among ECUs until a consensus is achievedamong the communicating ECUs.

In utilizing the centralized node, the network level diagnostic analyzer40 collects and manages the diagnostic data from the in-vehiclecommunication system collectively. The network level diagnostic analyzer40 performs network level diagnostics which includes the diagnostics ofthe communication bus 20 and of the nodes coupled to the communicationbus. The network level diagnostic analyzer 40 collects the node leveldiagnostic data from each of the ECUs and also the network diagnosticsperformed on the communication bus for collectively performingintegrated network level diagnostics for further isolating the fault.The fault detection at the network level may indicate whether the faultis isolated to the communication bus or whether the faults is isolatedto a coupling between the communication bus and the transmitting node orreceiving node.

Prognosis may also be performed at the communication layer level,integrated ECU level, and integrated network level. Integrated prognosisperformed at the network level may be used after fault isolation isdetected for estimating intermittent faults.

FIG. 3 illustrates a flow diagram for performing integrated diagnosticand prognosis analysis for the in-vehicle communication system. In step50, the routine is initiated. Diagnostic analysis is performed at boththe ECU node level and the network level.

In step 51, fault detection analysis is performed at each respectivecommunication layer for each ECU being analyzed. The fault detection foreach communication layer at the node level is analyzed independently ofthe other communication layers. The fault detection for eachcommunication layer is preferably performed concurrently; however, thefault detection for each communication layer may be performedsequentially. After fault detection is performed on each of thecommunication layers, the routine proceeds to step 52.

In step 52, fault detection analysis is performed on an integrated ECUnode level. For each ECU, the diagnostic data obtained from the analysisof each of the communication layers are collectively analyzed at the ECUnode level. This involves the integrated diagnostics and prognosis offault detection data at the multiple communication layers.

In step 53, network level fault detection analysis is performed on thecommunication bus. The network level fault detection analysis may beperformed concurrently with node level analysis and/or integrated nodelevel analysis. Alternatively, network level fault detection analysismay be performed sequentially, either before or after the node levelanalysis or integrated node level analysis. This includes monitoring anddetecting faults of the communication bus.

In step 54 integrated network level diagnostics and prognosis areperformed utilizing the data obtained in steps 51-53. The diagnostic andprognosis utilizes the ECU node level diagnostic and prognosis data, theintegrated node level diagnostic and prognosis data, and the networklevel communication bus fault detection data for collectively analyzingthe in-vehicle communication system and isolating the faults within thesystem.

In step 55, isolated faults are output for identifying the faults. Theidentified faults may be immediately output to a user such as a driverof a vehicle or a service technician servicing the vehicle.Alternatively, the identified faults may be stored in memory for laterretrieval by a service technician or other entity by an engineeringgroup for correcting and enhancing the in-vehicle communication system.In addition, the isolated faults may be used to perform prognosis ofintermittent faults within the in-vehicle communication system.

While certain embodiments of the present invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention as defined by the following claims.

What is claimed is:
 1. A method of diagnosing a fault in an in-vehiclecommunication system, the in-vehicle communication system including atransmitting node, at least one receiving node, and a networkcommunication bus coupling the transmitting node to the at least onereceiving node, each of the transmitting node and the at least onereceiving node including a plurality of communication layers forservicing messages within each of the nodes within the in-vehiclecommunication system, the plurality of communication layers of each nodeincluding at least an application layer, an interaction layer, a datalink layer, and a physical layer, the method comprising the steps of:transmitting a message from the transmitting node to the at least onereceiving node over the communication bus; applying a fault detectiontechnique within the transmitting node for detecting a fault within thetransmitting node; applying a fault detection technique within the atleast one receiving node for detecting a fault within the at least onereceiving node; applying a fault detection technique within the networkcommunication bus for detecting a fault within the communication bus;and an analyzer collectively analyzing results from each respectivedetection technique for isolating a fault within the in-vehiclecommunication system.
 2. The method of claim 1 wherein applying a faultdetection technique to the transmitting node includes applying arespective fault detection technique to each communication layer withinthe transmitting node.
 3. The method of claim 2 wherein each of thefault detection techniques applied in the transmitting node arecollectively analyzed for diagnosing and isolating a location of thefault within the transmitting node.
 4. The method of claim 3 whereinapplying a fault detection technique to the at least one receiving nodeincludes applying a respective fault detection technique to eachcommunication layer within the at least one receiving node.
 5. Themethod of claim 4 wherein each of the fault detection techniques appliedin the at least one receiving node are collectively analyzed fordiagnosing and isolating a location of the fault within the receivingnode.
 6. The method of claim 5 wherein an integrated diagnostictechnique is collectively applied to the in-vehicle communicationsystem, the integrated diagnostic technique performs integrateddiagnostic analysis on the collective analyzed diagnostics of the atleast one receiving node, the collective analyzed diagnostics of thetransmitting node, and the fault detection analysis of the communicationbus.
 7. The method of claim 6 wherein the analyzed diagnostics of eachnode are reported to a network level diagnostic module, wherein theintegrated diagnostic technique is performed by the network leveldiagnostic module.
 8. The method of claim 7 wherein a prognosis analysisis performed by the network level diagnostic module on the identifiedisolated fault for determining intermittent faults within the in-vehiclecommunication system.
 9. The method of claim 1 wherein identifying thefault includes identifying a software fault within a respective node.10. The method of claim 1 wherein identifying the fault includesidentifying a hardware fault within a respective node.
 11. The method ofclaim 10 wherein identifying the fault includes identifying a controllerfault within a respective node.
 12. The method of claim 10 whereinidentifying the fault includes identifying a transceiver fault within arespective node.
 13. The method of claim 10 wherein identifying thefault includes identifying a bus connector fault within a respectivenode.
 14. The method of claim 1 wherein identifying the fault includesidentifying a disconnection of a wire within the communication bus. 15.The method of claim 1 wherein identifying the fault includes identifyinga short between a wire and a ground within the communication bus. 16.The method of claim 1 wherein the identified fault is output utilizingan output device for identifying the fault.
 17. The method of claim 1wherein the identified fault is stored in a memory storage device. 18.The method of claim 1 wherein analyzer is comprised of a centralizednode dedicated to collectively analyzing the results of each respectivedetection technique for isolating the fault.
 19. The method of claim 1wherein the analyzer is comprised of resources across the plurality ofnodes in the in-vehicle communication system.
 20. The method of claim 19wherein resources include a controller in each node dedicated tocollectively analyzing the results of each respective detectiontechnique, the controller in each node collectively communicates withone another until a consensus is achieved among the communicating ECUsfor identifying the fault.